Victoria Police Chief Commissioner Ken Lay said police believe 12 of the 68 fires burning across the state were deliberately lit.

Most of those fires were sparked on the urban fringes of Melbourne, including three grass fires in Epping, in the city’s north.Detectives are now investigating those fires.

Meanwhile, a man who lit a fire at a Victorian camping site while a radio was airing total fire ban warnings has been interviewed by police.

Police said the 45-year-old was one of two men interviewed on Thursday over lighting a fire on a total fire ban day.

The man allegedly lit a campfire in Reeves Beach Camping Site in Yarram in Gippsland.

Police say when they arrived a radio was on in the background and was airing total fire ban warnings.

Officers also interviewed a 48-year-old man after he allegedly lit a campfire on Bullock Island in Lakes Entrance.

Inspector Shane Smith said lighting a fire on a total fire ban day was a criminal offence.

‘‘We’re lucky these fires did not get out of hand, but there is no telling the damage that can be done if a small fire turns into a larger one,’’ he said.

Bracing for blackouts

After Thursday night’s mass power outage across Melbourne, power companies are bracing for potential blackouts on Friday as the mercury rises.

United Energy spokesman Jai McDermott said the network had significant power outages in Frankston on Thursday night, after fire damaged electricity poles.

Mr McDermott said at 8am, just under 200 customers were experiencing a blackout, mainly in the Dandenong North and Malvern East areas. The company expects to restore power in those areas about 3pm on Friday.

He said that United Energy was working around the clock to fix any problems.

‘‘We have another long day ahead of us, and as a result, we had extra crews working throughout the night.

‘‘We’re facing another long day ahead of us, and hoping that the cooler weather might bring some relief,’’ Mr McDermott said.

Drew Douglas from Citi Power and Powercor Australia - the company responsible for Melbourne CBD (Citi Power) and western and central Victoria region (Powercor Australia) - said there were ‘‘fewer than 100 customers with power blackouts’’.

Mr Douglas said Powercor Australia was keeping ‘‘a close eye on western and central Victoria’’, an area which was close to the raging Grampians blaze.